OXYGEN ENRICHED AIR GASIFICATION IN AN EXPERIMENTAL TWO-STAGE GASIFIER

Gasification proposes to convert a large variety of biomass, including wastes, into a convenient fuel in the form of syngas. Syngas usually presents a lower heating value (LHV) below 6MJ/Nm3.This LHV is due to the high nitrogen content of syngas (45-50%) as air is usually used as the gasifying agent in small-scale applications. It is low in comparison to the LHV of natural gas; too low for some applications. The use of oxygen-enriched air reduces the nitrogen content of syngas and increases its LHV. This paper presents the preliminary results obtained on an experimental two-stage gasifier using a mixture of 50% of oxygen and 50% of nitrogen as the gasification agent. The syngas produced contains approximately 17% of nitrogen and has a LHV of 8.5MJ/Nm(3). The decrease of nitrogen content not only increases the LHV at the output but also increases the reactive zones temperature potentially allowing a better carbon conversion. The tests also show that there is no increase in the wear of the facility on a short term basis. This will need to be validated on longer experiments.